Presidential shingle,woven valley

[mathew stouffer]

I had trouble determining if this valley was installed correctly. JDLR, and I never see pres shingle woven valleys.

[H.G. Watson, Sr.]

From:

http://www.certainteed.com/resources/presidentialshakeinstall.pdfAttached

CertainTeed Shingle Applicator's Manual, Chapter 15, Presidential Shake (TM) and Presidential TL (TM) Shake Shingles (8 pages) see first page top left column for snipped quote below.


Open valleys are recommended; however, closed-cut valleys are also acceptable. Woven valleys are not recommended when applying Presidential and Presidential TL, because the laminated single can buckle and become damaged when shaped into the valley.

From second attached document, the ESR found here:

http://www.icc-es.org/reports/pdf_files/ICC-ES/ESR-1389.pdf

See some even stronger language in the ES Report, ESR-1389, see especially Section 4.1.2.4 Sealing and 4.1.3 Valley Construction, and 5.0 Conditions of Use language; the illustrations and their notations in Figure 4 on page 14 of 14; also note offsets illustrations in Figure 2 on page 11 of 14; and the notes regarding nailing patterns and "must" statements regarding cementing in Figure 1 on page 8 of 14, of the ES Report.


Valley Construction: Open valleys are recommended by CertainTeed, although closed-cut valleys may be used for Grand Manor, Centennial Slate, Carriage House, Presendential TL, Presidential Shake and Landmark TL shingles. Closed-cut valleys are recommended by CertainTeed for all other shingles. California closed-cut, or woven valleys must require that a 36-inch-wide (914 mm), 50-pound-per-square-foot (2.4 kg/sq. m) or greater, smooth-surfaced roll roofing, complyiing with ASTM D 6380, or specialty underlayment complying with ASTM D 1970, be installed vertically in the valley over required underlayment. The California valley methods must be limited to Landmark, Landmark-Woodscape, New Horizon, and Centennial Slate shingles for slopes of 4:12 or greater and are further described in Figure 4 of this report. Fasteners must not be placed within 6 inches (152 mm) of the valley centerline. For open valleys, corrosion-resistant metal valley flashing must be centered and placed vertically in the valley over the smooth-surfaced roll roofing, or specialty underlayment.

Corrosion-resistant metal valley flashing must be as follows:

- IBC: A minimum of 16 inches (406 mm) wide, complying with IBC Table 1507.2.9.2

- IRC: A minimum of 24 inches (610 mm) wide, complying with IRC Table 905.2.8.2.

Read through the entirety of both documents. You'll find quite a few "must" statements within the Recommended, Strongly Recommended, and "not recommended" statements. However, keep in mind the wind and cold climate sealing requirements for your region, snow loads, ice formation, freeze/thaw cycles, intense sun @ altitude, etc. and the style and type of these particular shingles and the roof slope, make a woven valley attempt less than wise.

It is not a properly executed true woven valley, courses not in alignment from the left, stagger pattern also seems off on the left, sides are exposed and reverse pitched and uncemented onto the right, there has apparently been no required sealing, or follow-up sealing after first year cycle exposure, the shingles apear to be delaminating and may have broken layers in addition to the curling. Some problems not keeping lines straight and all the courses from the left roof are running up over top those on the right. To me this looks like not truely woven/lapping.

IIRC your adoptions of IRC include ammendments which may apply to this subject area.

HTH.

[mathew stouffer]

Thanks HG, I looked and poked around at that damn valley for 30 min, it was tough to tell what the hell they did, and the thick shingles didn't make it easier. In the end i called it out, let the roofer deal with it.

[wayne soper]

That's why they call it dope

[Jim Robinson]

One of my friends liked to install the woven valley. I never did like the look or the function, and certainly didn't understand the logic behind the extra time involved. But that's just me.